1. Field of the Invention
The present invention relates generally to the formulation of a novel bleaching and cleaning composition. In particular, the subject invention is concerned with a detergent composition containing a halogenated glycoluril compound which is coated with a polymer which is able to hydrate and dissolve at a pH greater than 6.0. Pharmaceutically acceptable enteric coating polymers are particularly suitable in the practice of the present invention.
2. Description of the Related Art
It is known to include bleaching agents in cleaning products and in particular in detergent compositions for cleaning fabrics. Conventional bleaching agents include alkali metal hypochlorites, hydrogen peroxide and more recently water soluble peroxide adducts, e.g., alkali metal perborates, percarbonates, perphosphates and persilicates. For instance, chlorine dioxide is also known as a powerful oxidizing agent. Perborates are a popular fabric-safe bleach used at the present time.
It is also known that in the cleaning and bleaching of either colored or white fabrics, it is unsatisfactory to remove the stains from fabrics at the cost of fading the colors or degrading the fibers in the fabric during the bleaching process. Prior to this invention, difficult stains were removed either by repeated washing and bleaching steps or by increasing the concentration of bleach during the laundering process. The use of higher concentrations of bleach runs the risk of damage to the fabric fiber or localized bleaching of color in the fabric.
It has long been known that many compounds which contain a halogen atom in their structure have the possibility of acting as bleaching agent. A wide variety of suitable halogenated bleaching agents are known in the art. For instance, Slezak et al, "Halogenation of Glycoluril and Diuradopentane," Journal of Organic Chemistry, Vol. 25, pp. 660-661 (1959) describes several chlorinated glycoluril compounds.
At one time tetrachloroglycoluril was marketed by Diamond Alkali Company, now Diamond Shamrock, as a bleaching and sanitizing agent. It was also used in briquet form as a swimming pool disinfectant. However, the compound was limited by its solubility and commercial interest soon waned. Tetrachloroglycoluril is no longer used as a bleaching or sanitizing agent.
A number of processes are known in the art for coating halogen-containing bleaching or cleaning compounds in an attempt to develop a fabric-safe product. For instance, U.S. Pat. No. 4,725,378 discloses a composition useful for supplying a bleach over a period of time by contacting a polycarboxylic acid, a second polymeric compound and a chlorine-releasing agent under the proper conditions. U.S. Patent No. 3,715,184 suggests coating particles of acylated glycoluril compounds with watersoluble high molecular weight organic substances which are preferably capable of swelling in water.
U.S. Pat. No. 4,009,113 relates to the protection of solid precursors in powder detergent compositions using a hydrogen peroxide bleaching system. The finely divided precursor is formed into a composite particle which is then coated. The coated particle allows good dispersion of the precursor in the wash liquor.
U.K. Patent Specification No. 907,358 discloses coating a precursor, e.g., tetraacylmethylenediamine with a water-soluble material, e.g., a polyethylene glycol. The product is protected from the environment and has a slow rate of dissolution. In U.K. Patent Specification No. 1,204,123, there is described a method of protecting an adjunct in detergent compositions.
U.S. Pat. No. 4,728,453 discloses delayed-release hypohalite bleach compositions which include encapsulates having a granular, hypohalite-releasing core and a coating which delays release of the hypohalite ion and scavenging hypohalite ion when the encapsulates are exposed to an aqueous solution.
U.S. Pat. No. 4,136,052 provides a special coating which encapsulates the bleaching compound. An active chlorinating agent is surrounded by a first non-reactive coating combination of fatty acid and wax. A second coating is applied containing fatty acid with a material exhibiting inverse aqueous solubility with respect to temperature. The outer, second coating is more resistant to dissolution in hot than in cold water.
U.S. Pat. No. 4,741,858 discloses time-release bleaching compounds containing encapsulated hypochlorite bleaching agents. One embodiment includes sodium silicate-coated lithium hypochlorite. U.S. Pat. No. 4,124,734 discloses a fatty acid coating material wherein the fatty acid has 12-20 carbon atoms. U.S. Pat. No. 4,526,699 involves the use of a bleaching composition which consists of an N-halo compound with a coating comprising a silicate bound, hydrated, soluble inorganic salt and an alkali metal salt of boric acid. U.S. Pat. No. 3,908,045 discloses an encapsulation process for particles.
The search for a fabric-safe, easy-to-use laundry bleaching and detergent composition still exists.
Thus, there still remains a long felt need in this art for a cleaning and bleaching composition which does not adversely affect sensitive dyes, approaches the bleaching effect of sodium hypochlorite and, preferably, is available in powder form.